A. Purpose and Objectives This resource exists to provide investigators of the Cancer Center with access to expertise in flow cytometry and cell sorting. The facility is equipped with state-of-the-art instrumentation, and its staff is capable of performing a wide variety of experiments, for the analysis and separation of cell populations stained with fluorescent compounds. Flow cytometry and cell sorting continue to be essential for a wide variety of research programs at this Cancer Center, and open access to this facility for all investigators obviates the need for investigators to acquire the equipment, technology and experience individually. This facility has equipment and reagents that can be flexibly configured and used to perform a very wide range of experiments, so as to meet the varied needs of a large number of investigators.